Registration for Tracked Medical Tools and X-Ray Systems

ABSTRACT

In order to increase the accuracy of registration between a world coordinate system and an image coordinate system such that a tracked medical tool may be moved forward in the body of a patient without any additional or with limited live imaging, a method for registration of the tracked medical tool with an X-ray system is provided. The method includes receiving image data from the X-ray system at a plurality of time points, receiving tracking data from a tracking device of the tracked medical tool at the plurality of time points, and registering the world coordinate system and the image coordinate system based on the received image data and the received tracking data at the plurality of time points.

This application claims the benefit of U.S. Provisional Application No.61/764,768, filed on Feb. 14, 2013, the disclosure of which isincorporated herein.

FIELD

The present embodiments relate to registration for tracked medical toolsand X-ray systems.

BACKGROUND

Electromagnetic tracking may be provided in a number of medicalapplications. A path for a medical tool may be planed, the path may beoverlaid over an image, and the medical tool may be tracked along thepath. This tracking may be used for inserting a medical device (e.g., aneedle) for biopsy or local treatment of a tumor. The tracking may bevisualized using a volumetric pre-operation dataset such as a magneticresonance (MR) dataset or a computed tomography (CT) dataset.

Electromagnetic tracking may also be provided for the guidance ofintravascular devices such as, for example, catheters and guidewires.Pre-operation or intra-operation three dimensional (3D) images may beused as a 3D roadmap. An operator of the catheter, for example, mayfollow a planned path or a vessel along the 3D roadmap. The operator isto know where an actual position of the catheter is as the catheter ismoved within the body of a patient. The actual position of the cathetermay be obtained from one or more coils integrated into the catheter, forexample. The one or more coils are tracked by an electromagnetictracking system.

The electromagnetic tracking system knows a position of the one or morecoils integrated into the catheter in a coordinate system of theelectromagnetic tracking system (e.g., a world coordinate system). Theelectromagnetic tracking system, however, does not know the position ofthe one or more coils integrated into the catheter in a coordinatesystem (e.g., an image coordinate system) of a pre-operation scan (e.g.,an MR dataset or a CT volumetric dataset) or an intra-operation scan(e.g., a 3D angiographic dataset or a DynaCT dataset).

If registration between the world coordinate system and the imagecoordinate system is achieved with a high enough degree of accuracy, andthe morphological situation during an intervention does not change, thecatheter, for example, may be moved forward in the body of the patientwithout any additional live imaging (e.g., fluoroscopy or ultrasound).

In one example in the prior art, registration between the worldcoordinate system and the image coordinate system is provided by fixingthe mechanical relationship between an angiographic X-ray system and anElectromagnetic tracking system in combination with a calibration of thegeometry of the angiographic X-ray system. In another example in theprior art, the registration between the world coordinate system and theimage coordinate system is provided by a reference frame, which isvisible in a volume of interest, including reference markers (e.g.,fiducials) in a fixed relationship to a reference coil system.

SUMMARY

In order to increase the accuracy of registration between a worldcoordinate system and an image coordinate system such that a trackedmedical tool may be moved forward in the body of a patient without anyadditional or with limited live imaging, a method for registration ofthe tracked medical tool with an X-ray system is provided. The methodincludes receiving image data from the X-ray system at a plurality oftime points, receiving tracking data from a tracking device of thetracked medical tool at the plurality of time points, and registeringthe world coordinate system and the image coordinate system based on thereceived image data and the received tracking data at the plurality oftime points.

In a first aspect, a method for registration of an endovascular devicewith an X-ray system is provided. The endovascular device includes atracking device. The method includes receiving image data from the X-raysystem at a plurality of time points. The image data includes image datarepresenting at least a portion of the endovascular device in a firstcoordinate system as the endovascular devices moves within or throughthe first coordinate system. Tracking data is received from the trackingdevice at the plurality of time points. The tracking date represents aposition of the endovascular device in a second coordinate system. Aprocessor registers the second coordinate system with the firstcoordinate system based on the received image data and the receivedtracking data at the plurality of time points.

In a second aspect, a system for registration of a tracked tool with anX-ray system is provided. The tracked tool includes a tracking device.The system includes an X-ray system configured to generate image datarepresenting at least a portion of the tracked tool in a firstcoordinate system as the tracked tool moves within or through the firstcoordinate system. The system also includes a processor configured toreceive tracking data from the tracking device while the X-ray systemgenerates the image data. The tracking data represents a position of thetracked tool in a second coordinate system. The processor is alsoconfigured to register the second coordinate system with the firstcoordinate system based on the received image data and the receivedtracking data.

In a third aspect, a non-transitory computer-readable storage mediumthat stores instructions executable by one or more processors forregistration of data generated by a tracked medical tool with image datagenerated by an X-ray system is provided. The tracked medical toolincludes a tracking device. The instructions include receiving imagedata from the X-ray system at a plurality of time points. The image dataincludes image data representing at least a portion of the trackedmedical tool in a first coordinate system as the tracked medical toolmoves within or through the first coordinate system. The instructionsalso include receiving tracking data from the tracked medical tool atthe plurality of time points, the tracking data representing a positionof the tracked medical tool in a second coordinate system. Theinstructions include registering the second coordinate system with thefirst coordinate system based on the received image data and thereceived tracking data at the plurality of time points.

BRIEF DESCRIPTION OF THE DRAWINGS

The components and the FIGS. are not necessarily to scale. Emphasisinstead is placed on illustrating the principles of the invention. Inthe FIGS., like reference numerals designate corresponding partsthroughout the different views.

FIG. 1 is a flow chart diagram of a first embodiment of a method forregistering a tracked medical tool and an imaging system;

FIG. 2 illustrates and exemplary three dimensional (3D) reconstructionof a tracking marker after segmentation from a two dimensional (2D)image;

FIG. 3 is a flow chart diagram of a second embodiment of a method forregistering a tracked medical tool and an imaging system;

FIG. 4 illustrates an exemplary registration of a segmentedrepresentation of the tracked medical tool with a dataset based on datareceived from the tracked medical tool;

FIG. 5 illustrates exemplary correction vectors determined betweencorresponding points of the segmented representation of the trackedmedical tool with the dataset based on the data received from thetracked medical tool;

FIG. 6 is a flow chart diagram of a third embodiment of a method forregistering a tracked medical tool and an imaging system;

FIG. 7 illustrates motion of the tracked medical tool in 2D with thetracking marker visible;

FIG. 8 is a flow chart diagram of a fourth embodiment of a method forregistering a tracked medical tool and an imaging system;

FIG. 9 illustrates a backprojection of a segmented representation of thetracked medical tool into a blurred tool reconstruction;

FIG. 10 is a flow chart diagram of a fifth embodiment of a method forregistering a tracked medical tool and an imaging system;

FIG. 11 shows one embodiment of a system for registering an image systemand a therapy system; and

FIG. 12 shows one embodiment of an imaging system for registering datagenerated by the imaging system with data generated by a tracking deviceof a medical device or tool.

DETAILED DESCRIPTION

A system is provided for performing methods of registration for trackedendovascular tools and X-ray systems (e.g., cone-beam systems) withknown geometry. The system includes, for example, a tracked endovasculartool (e.g., a guidewire or a catheter) with distinct markers or trackingmarkers (e.g., tracking coils, RFID chips, or center-of-massrepresenting fiducials). One or more of the tracking markers are visiblein X-ray projections. The system also includes an X-ray system withavailable geometric data for distinct projection views.

For three dimensional (3D) registration with determined points andmultiple tracking markers, the tracked tool is moved into a cone-beamsystem field of view. A number, n, of projection images (e.g., two ormore projection images) are acquired. For each of the projection images,the imaging system geometry is known. Simultaneously, positions of oneor more tracking markers of the tracked tool are recorded. A 3D imagereconstruction is performed from the acquired projection images, and theone or more tracking markers are segmented from the 3D imagereconstructions. For 3D reconstruction of a tracking marker aftersegmentation in two dimensions, if the vector paths do not intersect, a3D point with a minimal distance to all vector paths is calculated andtaken as a best approximation of the 3D tracking marker position in animage domain (e.g., 3D image coordinate system). Alternatively, the oneor more tracking markers may be segmented from the projection images,and 3D positions may be reconstructed from the segmented projectionimages. The positions may be determined without segmentation.

With the tracked marker positions calculated for the 3D image coordinatesystem, corresponding 3D tool positions are collected in the worldcoordinate system from, for example, a tracking controller. The 3D toolpositions may be an average position of the tracking marker during imageacquisition. Point based registration is performed between the trackedmarker positions and the corresponding 3D tool positions.

For 3D registration without determined points but with self-calibrationand multiple markers, the tracked tool is moved into a cone-beam X-raysystem field of view. A number of projection images, n, are acquired.For each of the projection images, the X-ray system geometry is known. A3D image reconstruction is performed from the acquired projection views.The target of the 3D image reconstruction is to visualize the trackedtool. Filtering may be applied to isolate the tracked tool in theprojection images.

The tracked tool is segmented from the 3D image reconstruction. 3Dpositions of tracking markers of the tracked tool in the worldcoordinate system are collected from a tracking device of the trackedtool. A most distal and a most proximal tracked marker position may bedetermined using, for example, a specific ID for each of the trackingmarkers.

The 3D shape of the tracked tool in the 3D image reconstruction may bematched and/or fit to the 3D positions of the tracking markers of thetracked tool in the world coordinate system. Locations where thetracking marker position and the 3D shape coincide/are closest may beused as registration points.

Because error sources such as large metallic devices and even the humanbody may disturb the magnetic field, a self-calibration procedure mayalso be provided. A least squares match of a shape to the tracked markerpositions may be determined. Assuming the distortion caused by the errorsources is homogenous throughout the tracked tool, 3D correction vectorsare determined for each of the tracked marker positions. The determinedcorrection is then applied to the tracked marker positions duringtracking. The correction vectors may be extrapolated throughout thetrackable volume (e.g., the tracked tool).

If only one trackable marker is available on the tracked tool, a 3Ddigital subtraction angiography (DSA) and biplane fluoroscopy may beused. A 3D DSA is acquired. The tracked tool is advanced to a positionvisible in a biplane imaging system FOV. The position of the patient maychange, but the tracked tool is to be positioned in the 3D DSA structure(e.g., using a 3D/2D overlay of the reconstructed data on thefluoroscopic projection data).

Fluoroscopic images of the moving tracked tool are acquired in twoplanes (e.g., a vertical plane and a horizontal plane) using roadmapfunctionality. Simultaneously, the position of the trackable marker isrecorded. For each such acquired image pair and corresponding trackedtool position, a 3D position of the tracked tool or the trackable markeris triangulated within the 3D DSA.

If the trackable marker position is clearly visible and has beenextracted in the fluoroscopic images, the corresponding triangulated 3Dposition may be used for registration. If the trackable marker positionis not clearly visible, the known shape of the tracked tool (e.g., withmarker position) may be fit to the reconstructed/triangulated trackedtool, and the tracking marker position may be correlated. Fitting mayinclude a constraint deformation of the tracked tool (e.g., from astarting point of a straight line to the reconstructed shape).

With this correspondence established for all of the acquired image pairsand trackable marker positions, point based registration is used tocorrelate the image coordinate system with the world coordinate system.

If only one trackable marker is available on the tracked tool, the 3Ddigital subtraction angiography (DSA) may also be used with monoplanefluoroscopy. A 3D DSA may be acquired with the tracked tool (e.g., aguidewire) including an electromagnetic (EM)-trackable marker in thefield of view. A 3D native mask image (e.g., a non-contrast scan) and a3D DSA image of vasculature are reconstructed.

The trackable marker is extracted in the native mask 3D reconstruction(e.g., in the image coordinate system), and the extracted representationof the marker is matched with the position of the EM tracked markerposition (e.g., in the world coordinate system). A representation of thetracked tool is also extracted from the native mask 3D reconstruction,and the tool diameter in the representation of the tracked tool isincreased (e.g., by blurring or in-plane diameter dilation), thusproviding an altered representation of the tracked tool. Fluoroscopicimages of the moving tool are acquired (e.g., in a roadmap) while thetracking position of the trackable marker is simultaneously recorded.

The moving tracked tool is backprojected (e.g., a backprojected 2Dobject) into the 3D using the altered representation of the tracked toolas a constraining volume. If the EM-trackable marker may berecognized/segmented in the fluoroscopic image, only a representation ofthe EM-trackable marker may be backprojected.

A 3D image coordinate of the moving tracked tool is determined as anintersection point of the backprojected 2D object and the altered 3Drepresentation of the tracked tool. If there is more than oneintersection coordinate for the tracked tool, as well as the trackablemarker, the center of mass may be used as a first approximation of thetool/marker position.

The recorded 3D point pairs, the intersecting 2D fluoroscopicbackprojections, and the simultaneously recorded tracking positions forthe trackable marker may be used as a basis for a point based image toworld coordinate system registration, calibration, or transformation.

If only one trackable marker is available on the tracked tool, a 3D DSAmay be used alone. A tracked tool may be moved into a field of view of a3D DSA image acquisition, high enough into a vasculature of a patient,for example, to allow distal movement of the tracked tool with the fieldof view. The tracked tool may not overlay any vasculature of interest.

A 3D mask run is acquired during pull-back of the tracked tool. For eachacquired projection image, world coordinates for the tracked tool (e.g.,the trackable marker of the tracked tool) are recorded. A 3D fill run isalso acquired.

A 3D DSA and a 3D image from the acquired native mask run arereconstructed. The native mask will include a blurred reconstruction ofthe tracked tool due to the motion during the reconstruction. For eachacquired projection image in the native mask run (e.g., with the trackedtool moving from frame to frame), the tracked tool is extracted (e.g.,segmented) and backprojected into 3D.

An intersection of the backprojected tool and the blurred 3Dreconstruction is determined. If the trackable marker is clearly visiblein the projection image (e.g., the two dimensional (2D) projectionimage, a 3D intersection coordinate is determined. If the trackablemarker is not visible, knowledge of the position with respect to thetool shape is used to determine the position in 3D. If there are morethan one intersection coordinate for the tracked tool, as well as thetrackable marker, the center of mass may be used as a firstapproximation of the tool/marker position.

With the 3D marker position determined for each acquisition frame, thesimultaneously recorded tracking marker position is used to establishimage-to-world coordinate system registration.

FIG. 1 is a flow chart diagram of an embodiment of a method 100 forregistering a tracked medical tool and an imaging system. The trackedmedical tool may be, for example, a tracked endovascular tool such as aguidewire or a catheter. The tracked medical tool may include two ormore tracking markers. The two or more tracking markers may be visiblein an image generated by the imaging system, and each tracking marker ofthe one or more tracking markers may include a tracking device. Thetracking device may include, for example, a tracking coil or an RFIDchip. The tracking coil, for example, may generate an electromagnetic(EM) signal, and the generated EM signal may be read out by a processor(e.g., a processor separate from the tracking coil). The processor maydetermine a global position of the tracking marker (e.g., within aglobal coordinate system) based on the read out EM signal generated bythe tracking coil. Other tracking devices may be provided. The sametracking marker is both detectable from data of an imaging system anduseable for tracking. Alternatively, different devices on the same toolare used for each.

The imaging system may be any number of imaging systems. For example,the imaging system may be a cone-beam X-ray system. The cone-beam X-raysystem may be a C-arm X-ray system or may be a biplane X-ray system. Thecone-beam X-ray system may generate two-dimensional projection images,fluoroscopic images, angiographic images, or any number of other typesof images. Imaging systems other than X-ray imaging systems may also beused.

In act 102, the tracked medical tool is moved through a body of apatient into a field of view of the imaging system. In act 104, anumber, n, of 2D projection images (e.g., two or more projection images)are generated by a processor of the imaging system. Image data isreceived from a detector of the imaging system, for example, and theprocessor generates the n 2D projection images based on the receivedimage data. For each projection image of the n 2D projection images, thegeometry of the imaging system is known. The imaging system may generatethe n 2D projection images at different positions relative to thepatient. For example, the imaging system may include a C-arm, and anX-ray source and a detector attached to different ends of the C-arm. TheC-arm may be rotated around the patient, and the n 2D projection imagesare generated at different angles relative to the patient and thus thetracked medical tool.

In act 106, the processor reconstructs a 3D image from the n 2Dprojection images. In one embodiment, representations of the two or moretracking markers are segmented from and/or identified in thereconstructed 3D data or image. The representations of the two or moretracking markers may be automatically segmented from the reconstructed3D data. Alternatively, a user of the imaging system may identify aregion within the reconstructed image to be segmented using an inputdevice, and the processor may segment the representation of the two ormore tracking markers based on the identified region received from theinput device. In another embodiment, representations of the trackingmarkers may be segmented from the n 2D projection images, and thesegmented representations of the tracking markers may be reconstructedto identify 3D positions of the tracking markers.

FIG. 2 illustrates a 3D reconstruction of one of the tracking markersafter segmentation in the n 2D projection images. The embodiment of FIG.2 shows five 2D projection images 200 of the tracked medical tool 202generated by the processor of the imaging system. Three tracking markers204, for example, are visible in the five 2D projection images 200. Ifvector paths do not intersect after 3D reconstruction of a trackingmarker after segmentation in the 2D projection images, a 3D point with aminimal distance to all vector paths is calculated and taken as a bestapproximation of a 3D tracking marker position in a first coordinatesystem (e.g., the image coordinate system). Other methods (e.g.,averaging) may be used to determine the 3D tracking marker position inthe first coordinate system.

In act 108, a 3D position of the tracked medical tool and/or 3Dpositions of the tracking markers within a second coordinate system(e.g., the global coordinate system) are determined by the processorbased on, for example, signals emitted by the tracking devices of thetracking markers (e.g., EM signals emitted by the tracking coils of thetracking devices). The 3D positions of the tracking markers within thesecond coordinate system may be determined at a plurality of time pointscorresponding to the plurality of time points at which the 2D projectionimages are generated. In other words, the 2D projection images may begenerated and the 3D positions of the tracking markers within the secondcoordinate system may be determined simultaneously. In one embodiment,the 3D position for each of the tracking markers within the secondcoordinate system may be calculated by averaging the determined 3Dpositions within the second coordinate system for the tracking markerover the plurality of time points.

In act 110, the processor registers the 3D position data for thetracking markers within the first coordinate system from act 106 withthe 3D position data for the tracking markers within the secondcoordinate system from act 108. The registration may be a point basedregistration. The point based registration may include translation,rotation, etc. of one data set relative to the other. The resultantregistration may be saved to a memory of the imaging system for futuretracking of the tracked medical tool within the patient.

FIG. 3 is a flow chart diagram of an embodiment of a method 300 forregistering a tracked medical tool and an imaging system. The trackedmedical tool may include two or more tracking markers. The two or moretracking markers may not be visible in an image generated by the imagingsystem. The method illustrated by FIG. 3 may be used when the two ormore tracking markers are not visible in one or more of the imagesgenerated by the imaging system.

In act 302, the tracked medical tool is moved through a body of apatient into a field of view of the imaging system. In act 304, anumber, n, of 2D projection images (e.g., two or more projection images)are generated by a processor of the imaging system. For each projectionimage of the n 2D projection images, the geometry of the imaging systemis known. In one embodiment, hundreds of 2D projection images aregenerated by the processor the imaging system.

In act 306, the processor reconstructs a 3D image from the n 2Dprojection images. In one embodiment, filtering is applied to the 2Dprojection images to isolate the representations of the tracked medicaltool in the 2D projection images. A representation of the trackedmedical tool is segmented from the reconstructed 3D image. Therepresentation of the tracked medical tool may be automaticallysegmented from the reconstructed 3D image. Alternatively, a user of theimaging system may identify a region within the reconstructed image tobe segmented using an input device, and the processor may segment therepresentation of the tracked medical tool based on the identifiedregion received from the input device.

In act 308, a 3D position of the tracked medical tool and/or 3Dpositions of the tracking markers within a second coordinate system(e.g., the global coordinate system) are determined by the processorbased on, for example, signals emitted by the tracking devices of thetracking markers (e.g., EM signals emitted by the tracking coils of thetracking devices). The 3D positions of the tracking markers within thesecond coordinate system may be determined at a plurality of time pointscorresponding to the plurality of time points at which the 2D projectionimages are generated. In other words, the 2D projection images may begenerated and the 3D positions of the tracking markers within the secondcoordinate system may be determined simultaneously. In one embodiment,the 3D position for each of the tracking markers within the secondcoordinate system may be calculated by averaging the determined 3Dpositions within the second coordinate system for the tracking markerover the plurality of time points.

In act 310, the shape of the representation of the tracked medical toolsegmented from the reconstructed 3D image in act 306 is registered(e.g., matched and/or fit) with the determined 3D positions of thetracking markers within the second coordinate system from act 308. Forexample, one of the data sets (e.g., the segmented representation of thetracked medical tool) is registered (e.g., translated, rotated, etc.) tothe other of the data sets (e.g., the determined 3D positions of thetracking markers within the second coordinate system). The resultantregistration may be saved to a memory of the imaging system for futuretracking of the tracked medical tool within the patient.

FIG. 4 illustrates a representation 400 of the tracked medical toolsegmented from a reconstructed 3D image (e.g., from act 306) displayedwith determined 3D positions of the tracking markers within the secondcoordinate system (e.g., from act 308). In the embodiment shown in FIG.4, a guidewire is represented. Other tracked medical tools may berepresented.

The registration of act 310 may include the processor determining aleast squares match of the shape of the determined 3D positions of thetracking markers within the second coordinate system. The registrationmay thus be between the least squares curve and the segmentedrepresentation of the tracked tool. Other matches may be used.

Error sources such as large metallic devices and the human body maydisturb the magnetic field used with the tracking devices, for example.Accordingly, such error sources may affect the accuracy of the trackingdevices. Distortions may be assumed to be homogeneous throughout thetracked medical tool. 3D correction vectors may be determined for eachof the tracked marker positions based on a comparison between thedetermined least squares curve and the segmented representation of thetracked tool.

FIG. 5 illustrates exemplary correction vectors determined betweencorresponding points of the segmented representation of the trackedmedical tool with the data set generated based on data received from thetracked medical tool (e.g., the tracking devices). Correction vectorsare determined between corresponding points. The determined correctionvectors may be stored in a memory of the imaging system for futurecalibrations. The determined correction vectors are applied to thetracked marker positions and may be extrapolated throughout the trackedmedical tool.

FIG. 6 is a flow chart diagram of an embodiment of a method 600 forregistering a tracked medical tool and an imaging system. The method ofFIG. 6 may be used when the tracked medical tool includes a singlevisible tracking marker. The imaging system may include a biplane X-raysystem (e.g., a biplane fluoroscopy system) for the embodiment of FIG.6. The biplane X-ray system generates images in two different planes(e.g., a vertical plane and a horizontal plane) at the same time. Thebiplane X-ray system includes, for example, two X-ray sources and twocorresponding detectors that are rotatable around the patient.

In act 602, a 3D digital subtraction angiography (DSA) image isgenerated by the processor. Generation of the 3D DSA image includes theimaging system generating a plurality of 2D projection images of thetracked medical tool inside the body of the patient. The plurality of 2Dprojection images include 2D projection images generated based on datareceived when a contrast agent is injected into the patient and 2Dprojection images generated based on data received when the contrastagent is not injected into the patient. The processor reconstructs a 3Dmask image or a pre-contrast image based on the 2D projection imagesthat do not include the contrast agent, and reconstructs a 3D contrastimage based on the 2D projection images that do include the contrastagent. The processor generates the DSA image based on a subtraction ofthe 3D mask image from the 3D contrast image.

In act 604, the tracked medical tool is advanced to a position visiblein a field of view of the biplane imaging system. The position of thepatient may change, but the tracked medical tool is positioned in the 3DDSA structure (e.g., using a 3D/2D overlay).

In act 606, 2D projection image pairs (e.g., images in two planes) aregenerated by a processor of the imaging system. The 2D projection imagepairs are generated while the tracked medical tool moves through thefield of view of the biplane imaging system. Any number of 2D projectionimage pairs may be generated. Image data is received from the twodetectors of the imaging system, for example, and the processorgenerates the 2D projection image pairs based on the received imagedata. For each projection image, the geometry of the imaging system isknown.

A 3D position of the tracked medical tool and/or 3D positions of thetracking marker within a second coordinate system (e.g., the globalcoordinate system) are determined by the processor based on, forexample, signals emitted by the tracking devices of the (e.g., EMsignals emitted by the tracking coils of the tracking devices). The 3Dpositions of the tracking markers within the second coordinate systemmay be determined at a plurality of time points corresponding to theplurality of time points at which the 2D projection images aregenerated. In other words, the 2D projection images may be generated andthe 3D positions of the tracking markers within the second coordinatesystem may be determined simultaneously.

In act 608, the processor determines a 3D position of the trackedmedical tool or the tracking marker within a first coordinate system(e.g., the image coordinate system) for each of the generated 2Dprojection image pairs. This determination includes triangulating the 3Dposition of the tracked medical tool or the tracking marker inside the3D DSA image based on marker positions extracted (e.g., segmented) fromthe generated 2D projection image pairs.

FIG. 7 illustrates motion of the tracked medical tool in 2D with thetracking marker visible. The extracted tracking marker position istriangulated in 3D and recorded in a memory of the imaging system. Foreach point recorded this way, a tracking position is recorded.

If the tracking marker position is clearly visible and has beenextracted in the 2D projection images, the corresponding triangulated 3Dpositions are used for registration. If the tracking marker positionsare not clearly visible, the known shape of the tracked medical tool(e.g., with marker position) is fit to the reconstructed/triangulatedtoll, and the tracking marker position is correlated. In one embodiment,the fitting includes a constraint deformation of the tracked medicaltool (e.g., from a starting point of a straight line to thereconstructed shape).

In act 610, the processor registers the 3D position data for thetracking marker within the first coordinate system from act 608 with the3D position data for the tracking marker within the second coordinatesystem from act 606. The registration may be a point based registration.The point based registration may include translation, rotation, etc. ofone data set relative to the other. The resultant registration may besaved to a memory of the imaging system for future tracking of thetracked medical tool within the patient.

FIG. 8 is a flow chart diagram of an embodiment of a method 800 forregistering a tracked medical tool and an imaging system. The method ofFIG. 8 may be used when the tracked medical tool includes a singlevisible tracking marker. The imaging system may include a monoplaneX-ray system (e.g., a monoplane fluoroscopy X-ray system) for theembodiment of FIG. 8. The monoplane X-ray system may include, forexample, a C-arm with an X-ray source and a detector attached todifferent sides of the C-arm. The X-ray source and the detector may berotatable around the patient using the C-arm.

In act 802, a 3D digital subtraction angiography (DSA) image isgenerated by the processor. Generation of the 3D DSA image includes theimaging system generating a plurality of 2D projection images of thetracked medical tool inside the body of the patient. The plurality of 2Dprojection images include 2D projection images generated based on datareceived when a contrast agent is injected into the patient and 2Dprojection images generated based on data received when the contrastagent is not injected into the patient. The processor reconstructs a 3Dmask image or a pre-contrast image based on the 2D projection imagesthat do not include the contrast agent, and reconstructs a 3D contrastimage based on the 2D projection images that do include the contrastagent. The processor generates the DSA image based on a subtraction ofthe 3D mask image from the 3D contrast image.

In act 804, a representation of the tracking marker is segmented fromthe reconstructed 3D mask image within a first coordinate system (e.g.,the image coordinate system). The representation of the tracking markermay be automatically segmented from the reconstructed 3D mask image.Alternatively, a user of the imaging system may identify a region withinthe reconstructed 3D mask image to be segmented using an input device,and the processor may segment the representation of the tracking markerbased on the identified region received from the input device.

A 3D position of the tracked medical tool and/or 3D position of thetracking marker within a second coordinate system (e.g., the globalcoordinate system) is determined by the processor based on, for example,signals emitted by the tracking devices of the (e.g., EM signals emittedby the tracking coils of the tracking devices). The 3D position of thetracking marker within the second coordinate system may be determined atone or more time points corresponding to the one or more time points atwhich the 2D projection images are generated. In other words, the 2Dprojection images may be generated and the 3D positions of the trackingmarkers within the second coordinate system may be determinedsimultaneously.

In act 806, a representation of the tracked medical tool is segmented(e.g., extracted) from the reconstructed 3D mask image. Therepresentation of the tracked medical tool segmented from thereconstructed 3D mask image may be altered. For example, a tool diameterof the segmented representation of the tracked medical tool may beincreased. In one embodiment, the tool diameter is increased by blurringor in-plane diameter dilation. The segmented representation of thetracked medical tool may be altered in other ways.

In act 808, the tracked medical tool is moved through the body of thepatient within a field of view of the imaging system. A number of 2Dfluoroscopic images are generated by the processor of the imaging systembased on image data received at the detector of the imaging system, asthe tracked medical tool moves through the field of view of the imagingsystem. For each of the 2D fluoroscopic images, the geometry of theimaging system is known. Any number of 2D fluoroscopic images may begenerated.

A 3D position of the tracked medical tool and/or a 3D position of thetracking marker within a second coordinate system (e.g., the globalcoordinate system) is determined by the processor based on, for example,signals emitted by the tracking devices of the (e.g., EM signals emittedby the tracking coils of the tracking devices). The 3D position of thetracking marker within the second coordinate system may be determined ata plurality of time points corresponding to the plurality of time pointsat which 2D fluoroscopic images are generated. In other words, the 2Dfluoroscopic images may be generated and the 3D position of the trackingmarker within the second coordinate system may be determinedsimultaneously.

In act 810, the processor backprojects the 2D fluoroscopic images of themoving tool into the 3D using the altered segmented representation ofthe tracked medical tool as a constraining volume. In one embodiment, ifthe tracking marker is identifiable in the 2D fluoroscopic images and arepresentation of the tracking marker may be segmented from the 2Dfluoroscopic images, only the representation of the tracking marker isbackprojected.

In act 812, the processor determines a 3D image coordinate of thetracked medical tool and/or the tracking marker within the firstcoordinate system. This determination includes the processor determiningan intersection point of the backprojected 2D object (e.g., the movingtool or the tracking marker) with the altered segmented representationof the tracked medical tool.

FIG. 9 shows a backprojection of a segmented representation of thetracked medical tool into a blurred tool reconstruction. Reconstructedvascular structure 900 acts as a constraining volume, and anintersection point 902 of the backprojected 2D object 904 with thealtered segmented representation of the tracked medical tool 906 definesthe 3D image coordinate of the tracked medical tool. In one embodiment,if there is more than one intersection coordinate for the trackedmedical tool 906 or the tracking marker, the center of mass may be usedas a first approximation of the tool/marker position.

In act 814, the processor registers the 3D position data for thetracking marker within the first coordinate system from act 812 with the3D position data for the tracking marker within the second coordinatesystem from act 808. The registration may be a point based registration.The point based registration may include translation, rotation, etc. ofone data set relative to the other. The resultant registration may besaved to a memory of the imaging system for future tracking of thetracked medical tool within the patient.

FIG. 10 is a flow chart diagram of one embodiment of a method 1000 forregistering a tracked medical tool and an imaging system. The method ofFIG. 10 may be used when the tracked medical tool includes a singlevisible tracking marker. The imaging system may include a monoplaneX-ray system (e.g., a monoplane fluoroscopy X-ray system) for theembodiment of FIG. 10. The monoplane X-ray system may include, forexample, a C-arm with an X-ray source and a detector attached todifferent sides of the C-arm. The X-ray source and the detector may berotatable around the patient using the C-arm. Other imaging systems maybe used.

In act 1002, a tracked medical tool is moved into a field of view of a3D image acquisition. The tracked medical tool may be positioned withinthe field of view such that the tracked medical tool may move distallywithin the field of view. The tracked medical tool may be positionedwithin the field of view such that the tracked medical tool does notoverlay any vasculature of interest.

In act 1004, the processor generates a 3D mask image in a 3D mask run.The 3D mask image is generated during pull back of the tracked medicaltool. Generation of the 3D mask image includes the imaging systemgenerating 2D projection images of the tracked medical tool inside thebody of the patient when no contrast agent is injected into the patient.The processor reconstructs the 3D mask image based on the 2D projectionimages that do not include the contrast agent. The 3D mask imageincludes a blurred reconstruction of the tracked medical tool due to themotion of the tracked medical tool during the acquisition.

A 3D position of the tracked medical tool and/or 3D position of thetracking marker within a second coordinate system (e.g., the globalcoordinate system) is determined by the processor based on, for example,signals emitted by the tracking devices of the (e.g., EM signals emittedby the tracking coils of the tracking devices). The 3D position of thetracked medical tool within the second coordinate system may bedetermined at a plurality of time points corresponding to the pluralityof time points at which the 2D projection images are generated duringthe 3D mask run. In other words, the 2D projection images may begenerated and the 3D position of the tracked medical tool within thesecond coordinate system may be determined simultaneously.

In act 1006, the processor generates a 3D DSA image. A plurality of 2Dprojection images are generated based on data received from the detectorduring imaging when a contrast agent is injected into the patient. Theprocessor reconstructs a 3D contrast image based on the 2D projectionimages that include the contrast agent. The processor generates the DSAimage based on a subtraction of the 3D mask image from the 3D contrastimage.

In act 1008, a representation of the tracked medical tool is segmented(e.g., extracted) from each 2D projection image generated in the 3D maskrun (e.g., with the tracked medical tool moving from frame to frame).The representations of the tracked medical tool are backprojected into3D.

In act 1010, an intersection of the backprojected tracked medical toolfrom act 1008 with the blurred reconstruction of the tracked medicaltool of act 1004 is determined. If the tracking marker is clearlyvisible in 2D, the 3D intersection coordinate may be determined and usedas the 3D position of the tracked medical tool and/or the trackingmarker within a first coordinate system (e.g., the imaging coordinatesystem). If the tracking marker is not clearly visible in 2D, a methodsimilar to the embodiment illustrated in FIG. 8 may be used to determinethe 3D position of the tracking marker and/or the tracked medical tool.If there is more than one intersection coordinate for the trackedmedical tool and/or the tracking marker, the center of mass may be usedas a first approximation of the tracked medical tool/tracking marker.

In act 1012, the processor registers the 3D position data for thetracking marker within the first coordinate system from act 1010 withthe 3D position data for the tracking marker within the secondcoordinate system from act 1004. The registration may be a point basedregistration. The point based registration may include translation,rotation, etc. of one data set relative to the other. The resultantregistration may be saved to a memory of the imaging system for futuretracking of the tracked medical tool within the patient.

FIG. 11 shows one embodiment of a system (e.g., a registration system)for registering an image system and a therapy system. The registrationsystem may be used in the methods described above. The registrationsystem 1100 may include one or more imaging devices 1102 (e.g., animaging device), one or more image processing systems 1104 (e.g., animage processing system), and one or more treatment devices 1106 (e.g.,a treatment device). A dataset representing a two-dimensional (2D) or athree-dimensional (3D) (e.g., volumetric) region may be acquired usingthe one or more imaging devices 1102 and the image processing system1104 (e.g., an imaging system). The 2D dataset or the 3D dataset may beobtained contemporaneously with the panning and/or execution of amedical treatment procedure or at an earlier time. Additional, differentor fewer components may be provided.

In one embodiment, the imaging system 1102, 1104 is, for example, acone-beam X-ray system. The cone-beam X-ray system 1102, 1104 maygenerate 2D projection images, 3D images reconstructed from the 2Dprojection images, fluoroscopic images, DSA images, or a combinationthereof. The cone-beam X-ray system 1102, 1104 may generate any numberof other images. The imaging system 1102, 1104 may be used to provideaccurate registration between the imaging system 1102, 1104 and thetreatment 1106 device such that a trackable device of the treatmentdevice 1106 may be moved within a body of a patient without anyadditional live imaging such as, for example, fluoroscopy or ultrasoundafter registration. For example, the image processing system 1104 is aworkstation for registering data generated by a tracking device of thetreatment device 1106 with data generated by the cone-beam X-ray system1102, 1104. In other embodiments, the imaging system 1102, 1104 mayinclude, for example, a medical workstation, a computed tomography (CT)system, an ultrasound system, a positron emission tomography (PET)system, an angiography system, a fluoroscopy, an x-ray system, any othernow known or later developed imaging system, or a combination thereof.The workstation 1104 receives data representing or images of the patient(e.g., including at least part of the body of the patient and thetreatment device 106) generated by the imaging device 1102.

The treatment device 1106 may be registered with the imaging system1102, 1104 using the imaging system 1102, 1104 and a tracking device ofthe treatment device. The treatment device 1106 may be any number oftreatment devices including, for example, a tracked endovascular toolsuch as a guidewire or a catheter. The tracked endovascular tool 1106may include one or more trackable markers (e.g., markers). The markersmay include, for example tracking coils. The markers may thus act as thetracking device for the tracked endovascular tool 1106. The therapysystem 1100 may include more or fewer components.

FIG. 12 shows one embodiment of an imaging system 1200 for registeringdata generated by the imaging system 1200 with data generated by atracking device of a medical device or tool (e.g., a marker of themedical device or tool). The imaging system 1200 may correspond to theimaging system 1102, 1104 and may be used in the methods describedabove. The system 1200 is an X-ray imaging system (e.g., a cone-beamX-ray system), but may be a computer, workstation, database, server, orother system. The system 1200 includes a processor 1204, a memory 1208,and a display 1212. In other embodiments, the system 1200 may includeadditional, different, or fewer components. For example, the system 1200may include an x-ray source and detector.

The memory 1208 is a buffer, cache, RAM, removable media, hard drive,magnetic, optical, database, or other now known or later developedmemory. The memory 1208 is a single device or group of two or moredevices. The memory 1208 is shown within the system 1200, but may beoutside or remote from other components of the system 1200, such as adatabase or PACS memory.

The memory 1208 stores medical imaging data (e.g., frames of medicalimaging data). Any type of medical imaging data (e.g., fluoroscopy,magnetic resonance, CT, etc., imaging data) may be stored. For example,a sequence of frames of fluoroscopy imaging data is stored. As anotherexample, a sequence of frames of DSA imaging data is stored. Thesequence is acquired over seconds or minutes. The medical images are ofa region including, for example, a vessel, a guidewire or catheter,and/or markers (e.g., a marker on the catheter). The catheter, forexample, may be introduced during acquisition of the sequence or mayalready be in place during the acquisition. The vessel may or may notinclude a guide wire for placement of the catheter. The data includes arepresentation of one or more markers for the catheter, for example.Alternatively, the medical image data is transferred to the processor1204 from another device with or without storage in the memory 1208.

For real-time imaging, the medical data bypasses the memory 1208, istemporarily stored in the memory 1208, or is loaded from the memory1208. Real-time imaging may allow delay of a fraction of seconds, oreven seconds, between acquisition of data and imaging. For example,real-time imaging is provided by generating images of the sequencesubstantially simultaneously with the acquisition of the data byscanning. To allow better visualization of the catheter (e.g., catheterswith less metal or radio opaque materials), for example, an enhancedcatheter image may be generated. In alternative embodiments, the imagedata is stored in the memory 1208 from a previous imaging session andused for detecting markers and/or generating catheter enhanced images.

The memory 1208 is additionally or alternatively a non-transitorycomputer readable storage medium with processing instructions. Thememory 1208 stores data representing instructions executable by theprogrammed processor 1204 for marker detection in medical imaging of acatheter. The instructions for implementing the processes, methodsand/or techniques discussed herein are provided on computer-readablestorage media or memories, such as a cache, buffer, RAM, removablemedia, hard drive or other computer readable storage media. Computerreadable storage media include various types of volatile andnon-volatile storage media. The functions, acts or tasks illustrated inthe figures or described herein are executed in response to one or moresets of instructions stored in or on computer readable storage media.The functions, acts or tasks are independent of the particular type ofinstructions set, storage media, processor or processing strategy andmay be performed by software, hardware, integrated circuits, firmware,micro code and the like, operating alone or in combination. Likewise,processing strategies may include multiprocessing, multitasking,parallel processing and the like. In one embodiment, the instructionsare stored on a removable media device for reading by local or remotesystems. In other embodiments, the instructions are stored in a remotelocation for transfer through a computer network or over telephonelines. In yet other embodiments, the instructions are stored within agiven computer, CPU, GPU, or system.

The processor 1204 is a general processor, digital signal processor,graphics processing unit, application specific integrated circuit, fieldprogrammable gate array, digital circuit, analog circuit, combinationsthereof, or other now known or later developed device for processingframes of data for medical images. The processor 1204 is a singledevice, a plurality of devices, or a network. For more than one device,parallel or sequential division of processing may be used. Differentdevices making up the processor 1204 may perform different functions,such as a marker detector and a separate device for generating acatheter enhanced image. In one embodiment, the processor 1204 is acontrol processor or other processor of a medical diagnostic imagingsystem, such as a cone-beam X-ray imaging system processor. Theprocessor 1204 operates pursuant to stored instructions to performvarious acts described herein, such as obtaining frames of image data,determining a plurality of candidate markers, automatically initializinga detector, tracking one or more markers, providing an image of thecatheter based on the tracking, registering, or combinations thereof.

The processor 1204 is configured to perform any or all of theabove-described acts (e.g., the acts illustrated in FIGS. 1-10). Theprocessor 1204 is configured to obtain a plurality of frames of imagedata. The processor 1204 is configured to determine a plurality ofcandidate markers for the catheter, for example, in the plurality offrames of image data. The processor 1204 is configured to detect one ormore candidate markers from the plurality of candidate markers. Theprocessor 1204 is configured to automatically initialize the detectionusing a subset of frames of the image data from the plurality of framesof image data. The processor 1204 is configured to detect based, atleast in part, on the automatic initialization. The processor 1204 isconfigured to detect in real-time.

The display 1212 is a CRT, LCD, plasma, projector, printer, or otheroutput device for showing an image. The display 1212 displays an imageof two or more markers. A catheter enhanced image with markers enhancedand/or highlighted may be displayed. An image of marker characteristicsmay be displayed, such as displaying a value representing the distancebetween markers. In other embodiments, the markers are not displayed,are displayed to indicate the location, or are merely displayed as partof an image without highlighting or enhancement.

Prior to the methods detailed above, the registration between anintra-operative dataset and a tracking mechanism was performed usingspecific registration and reference markers positioned outside thepatient or required a work intensive integration with an interventionalimaging device. With the registration provided by the presentembodiments, the registration may be performed online, the registrationdoes not require any registration markers positioned on the patient andinside a field of view of the interventional imaging device, or a fixedconnection to a C-arm of the interventional imaging device. Accordingly,the registration markers are close to the region of interest, which mayprovide a higher tracking accuracy. In summary, the registrationprovided by the present embodiments, provides for faster registrationand higher tracking accuracy than the registration methods of the priorart. Further, there is no need to change the acquired field of view, andthere is no extra registration step to be performed by the user.

While the present invention has been described above by reference tovarious embodiments, it should be understood that many changes andmodifications can be made to the described embodiments. It is thereforeintended that the foregoing description be regarded as illustrativerather than limiting, and that it be understood that all equivalentsand/or combinations of embodiments are intended to be included in thisdescription.

1. A method for registration of an endovascular device with an X-raysystem, the endovascular device comprising a tracking device, the methodcomprising: receiving image data from the X-ray system at a plurality oftime points, the image data comprising image data representing at leasta portion of the endovascular device in a first coordinate system as theendovascular device moves within or through the first coordinate system;receiving tracking data from the tracking device at the plurality oftime points, the tracking data representing a position of theendovascular device in a second coordinate system; registering, by aprocessor, the second coordinate system with the first coordinate systembased on the received image data and the received tracking data at theplurality of time points.
 2. The method of claim 1, further comprising:generating, by the processor, a plurality of projection images based onthe received image data from the X-ray system; and calculating, by theprocessor, positions of one or more markers of the tracking devicewithin the first coordinate system, the first coordinate system being athree-dimensional (3D) image coordinate system, wherein the registeringcomprises performing point based registration between the calculatedpositions of the one or more markers of the tracking device and thereceived tracking data from the tracking device.
 3. The method of claim2, wherein the calculating comprises: generating a three-dimensional(3D) image based on the plurality of generated projection images andsegmenting the one or more markers from the 3D image; or segmenting theone or more markers of the tracking device from the plurality ofprojection images and reconstructing a 3D image of the one or moremarkers.
 4. The method of claim 1, further comprising: generating, bythe processor, a plurality of projection images based on the receivedimage data from the X-ray system; generating a three-dimensional (3D)image based on the plurality of generated projection images, thegenerated 3D image representing at least the portion of the endovasculardevice; and segmenting at least the portion of the endovascular devicefrom the 3D image, wherein receiving the tracking data comprisesreceiving data representing positions of one or more tracking markers ofthe tracking device in the second coordinate system from the trackingdevice, and wherein the registering comprises matching the segmentedportion of the endovascular device from the 3D image to the receiveddata representing the positions of the one or more tracking markers ofthe tracking device.
 5. The method of claim 4, further comprisingfiltering the plurality of projection images, the filtering isolatingthe endovascular device within the plurality of projection images. 6.The method of claim 1, wherein the received image data is received firstimage data, and wherein the method further comprises: receiving secondimage data from the X-ray system or another X-ray system, the secondimage data representing an object in which the endovascular device isdisposable, the received second image data comprising image datarepresenting the object with a contrast agent injected and image datarepresenting the object with no contrast agent injected; and generatinga three dimensional (3D) digital subtraction angiography (DSA) image ofthe object based on the received second image data.
 7. The method ofclaim 6, further comprising: generating one or more fluoroscopic imagepairs of at least the portion of the endovascular device based on thereceived first image data, fluoroscopic images of each of the one ormore generated fluoroscopic image pairs being in different planes;triangulating a 3D position of one or more markers of the trackingdevice within the 3D DSA image based on the one or more generatedfluoroscopic image pairs, wherein the registering comprises performingpoint based registration between the triangulated 3D position of the oneor more markers of the tracking device and the received tracking datafrom the tracking device.
 8. The method of claim 6, further comprising:generating, by the processor, a plurality of fluoroscopic images basedon the received first image data; and segmenting a representation of anelectromagnetic (EM) trackable marker of the tracking device or arepresentation of the endovascular device from each fluoroscopic imageof the plurality of fluoroscopic images.
 9. The method of claim 8,wherein receiving the second image data comprises receiving second imagedata that represents the object and at least the portion of theendovascular device, at least a portion of the second image datarepresenting the EM trackable marker, the received tracking datacomprising tracking data representing a position of the EM trackablemarker in the second coordinate system at the plurality of time pointsand another time point, and wherein the generating of the 3D DSA imagecomprises generating a 3D DSA image of the object and at least theportion of the endovascular device based on the received second imagedata.
 10. The method of claim 9, further comprising: generating a 3Dmask image of the object and at least the portion of the endovasculardevice based on the received second image data; segmenting arepresentation of the EM trackable marker and a representation of theendovascular device from the 3D mask image; matching the representationof the EM trackable marker segmented from the 3D mask image with thetracking data representing the position of the EM trackable marker inthe second coordinate system at the other time point; altering therepresentation of the endovascular device segmented from the 3D maskimage, the altering comprising increasing a diameter of therepresentation of the endovascular device segmented from the 3D maskimage; backprojecting the representation of the EM trackable marker orthe representation of the endovascular device segmented from eachfluoroscopic image of the plurality of fluoroscopic images into thealtered segmented representation of the endovascular device; anddetermining a position of at least the portion of the endovasculardevice in the first coordinate system, the determining comprisingidentifying one or more intersection points of the backprojectedrepresentation of the EM trackable marker or the backprojectedrepresentation of the endovascular device with the altered segmentedrepresentation of the endovascular device, wherein the registeringcomprises performing point based registration between the one or moreintersection points and a portion of the received tracking data from thetracking device.
 11. The method of claim 1, wherein receiving the imagedata comprises receiving image data representing an object in which theendovascular device is disposable, the received image data comprisingimage data representing the object with a contrast agent injected andimage data representing the object with no contrast agent injected,wherein the method further comprises: generating a plurality ofprojection images based on the received image data from the X-raysystem; generating a 3D mask image of the object and at least theportion of the endovascular device based on the plurality of generatedprojection images, the generated 3D mask image including areconstruction of the endovascular device; generating a threedimensional (3D) digital subtraction angiography (DSA) image based onthe received image data and the generated 3D mask image.
 12. The methodof claim 11, further comprising: segmenting a representation of theendovascular device from each projection image of the plurality ofprojection images; backprojecting the segmented representation of theendovascular device into 3D; and determining an intersection of thebackprojected segmented representation of the endovascular device withthe reconstruction of the endovascular device, wherein the registeringcomprises performing point based registration between the determinedintersection and the received tracking data from the tracking device.13. A system for registration of a tracked tool with an X-ray system,the tracked tool comprising a tracking device, the system comprising: anX-ray system configured to generate image data representing at least aportion of the tracked tool in a first coordinate system as the trackedtool moves within or through the first coordinate system; and aprocessor configured to: receive tracking data from the tracking devicewhile the X-ray system generates the image data, the tracking datarepresenting a position of the tracked tool in a second coordinatesystem; registering the second coordinate system with the firstcoordinate system based on the received image data and the receivedtracking data.
 14. The system of claim 13, wherein the tracked toolcomprises a guidewire or a catheter.
 15. The system of claim 13, whereinthe tracking devices comprises tracking coils, RFID chips,center-of-mass fiducials, an electromagnetically trackable marker, or acombination thereof.
 16. The system of claim 13, wherein the X-raysystem comprises a biplane fluoroscopy imaging system.
 17. In anon-transitory computer-readable storage medium that stores instructionsexecutable by one or more processors for registration of data generatedby a tracked medical tool with image data generated by an X-ray system,the tracked medical tool comprising a tracking device, the instructionscomprising: receiving image data from the X-ray system at a plurality oftime points, the image data comprising image data representing at leasta portion of the tracked medical tool in a first coordinate system asthe tracked medical tool moves within or through the first coordinatesystem; receiving tracking data from the tracked medical tool at theplurality of time points, the tracking data representing a position ofthe tracked medical tool in a second coordinate system; registering thesecond coordinate system with the first coordinate system based on thereceived image data and the received tracking data at the plurality oftime points.
 18. The non-transitory computer-readable storage medium ofclaim 17, wherein the instructions further comprise: generating aplurality of projection images based on the received image data from theX-ray system; and calculating positions of one or more markers of thetracking device within the first coordinate system, the first coordinatesystem being a three-dimensional (3D) image coordinate system, whereinthe registering comprises performing point based registration betweenthe calculated positions of the one or more markers of the trackingdevice and the received tracking data from the tracking device, andwherein the calculating comprises: generating a three-dimensional (3D)image based on the plurality of generated projection images andsegmenting the one or more markers from the 3D image; or segmenting theone or more markers of the tracking device from the plurality ofprojection images and reconstructing a 3D image of the one or moremarkers.
 19. The non-transitory computer-readable storage medium ofclaim 17, further comprising: generating a plurality of projectionimages based on the received image data from the X-ray system; filteringthe plurality of projection images, the filtering isolating the trackedmedical tool within the plurality of projection images; generating athree-dimensional (3D) image based on the plurality of generatedprojection images, the generated 3D image representing at least theportion of the tracked medical tool; and segmenting at least the portionof the tracked medical tool from the 3D image, wherein receiving thetracking data comprises receiving data representing positions of one ormore tracking markers of the tracking device in the second coordinatesystem from the tracking device, and wherein the registering comprisesmatching the segmented portion of the tracked medical tool from the 3Dimage to the received data representing the positions of the one or moretracking markers of the tracking device.
 20. The non-transitorycomputer-readable storage medium of claim 17, wherein the received imagedata is received first image data, wherein the method further comprises:receiving second image data from the X-ray system or another X-raysystem, the second image data representing an object in which thetracked medical tool is disposable, the received second image datacomprising image data representing the object with a contrast agentinjected and image data representing the object with no contrast agentinjected; and generating a three dimensional (3D) digital subtractionangiography (DSA) image of the object based on the received second imagedata; generating one or more fluoroscopic image pairs of at least theportion of the tracked medical tool based on the received first imagedata, fluoroscopic images of each of the one or more generatedfluoroscopic image pairs being in different planes; and triangulating a3D position of one or more markers of the tracking device within the 3DDSA image based on the one or more generated fluoroscopic image pairs,wherein the registering comprises performing point based registrationbetween the triangulated 3D position of the one or more markers of thetracking device and the received tracking data from the tracking device.